In drawing distinctions between terms such as ignorance, simple-mindedness, foolishness, mockery, and scoffing, I would say that it's a matter of the mindset of each particular individual.
Ignorance by itself is not necessarily a negative attribute. No person possesses perfect knowledge. (As someone has said, "We are all ignorant -- just about different things.")
Also, the Bible -- both in the Mosaic Law (as noted in Leviticus 4, for example), as well as mentioned by Jesus in the Gospels (Luke 12:47-48) -- draws a distinction between sins that are committed through ignorance, and those that are committed deliberately or with knowledge that the action is wrong, by specifying or speaking of a lesser penalty for sins that are committed unintentionally, or through ignorance.
However, everyone has the potential to actively acquire knowledge (both through learning and experience), and also to then act with wisdom on the basis of the knowledge that they have -- in other words, to apply that knowledge to arrive at correct conclusions, and to use those conclusions as a basis for acting in a manner that benefits themselves and others. And Christians are also encouraged to "grow in the grace and knowledge of our Lord and Savior Jesus Christ" (2 Peter 3:18).
But problems arise when an individual refuses to expand his knowledge or to receive instruction or correction, because he believes that he knows everything that he needs to know, and also believes that everything he knows is correct (although it may not be), and then uses the limited knowledge that he does have as a basis for reaching wrong conclusions, or for acting foolishly or destructively.
It is people who do not feel the need to expand or correct their body of knowledge; or who deliberately refuse to make wise decisions, or to be instructed in how to make wise decisions, on the basis of that knowledge; or who actively disdain the pursuit of knowledge at all; or who even look with disapproval or contempt upon those who are seeking to acquire knowledge and apply it wisely, whom the book of Proverbs characterizes by terms such as 'simpletons', 'fools', 'scoffers', and 'mockers', respectively.
Also, remember that, as Solomon said elsewhere in Proverbs, "The fear of the Lord is the beginning of wisdom." (Proverbs 9:10). Having the right relationship between oneself and God (who DOES possess all knowledge), and knowing what God's word reveals about Him and about man, can provide the basic conceptual framework that leads to correct assumptions and conclusions in the processing of acquired knowledge, and to the wise choice of actions based on that knowledge.